It has happened twice. Both times due to not prejerking the same day. I have found 2 to 3 hours before session works best. I was surprised and embarrassed. Both times, the session continued, I think with flogging and I had to ask the session end early after trying for about three minutes. It was a combo of having lost interest and the pain was magnified and just wanting to get out of there as soon as possible. Both times had involved the tying of my balls or dick just prior to ejaculation